Originally Posted by
Antarius
They work perfectly for you listening and others hearing you, yes. However, since they do a good job at blocking ambient noise, many people naturally do talk louder.
They (phone and earbud/headpones manufacturers) need to implement what's called "sidetone". When you talk on a regular phone (ok, when you USED to use a regular phone) you get to hear your voice through the earpiece too, otherwise it sounds "weird" to you because the one ear is covered.
Apple does this when you use AirPods Pro on an iPhone if you enable "Transparency Mode".